SOCKET.H(3HEAD) Headers SOCKET.H(3HEAD)
NAME
socket.h, socket, CMSG_DATA, CMSG_FIRSTHDR, CMSG_LEN, CMSG_NXTHDR,
CMSG_SPACE - Internet Protocol family
SYNOPSIS
#include <sys/socket.h>DESCRIPTION
The
<sys/socket.h> header defines the unsigned integral type
sa_family_t through
typedef.
The
<sys/socket.h> header defines the
sockaddr structure that includes
the following members:
sa_family_t sa_family /* address family */
char sa_data[] /* socket address (variable-length
data) */
libxnet Interfaces
The
<sys/socket.h> header defines the
msghdr structure for
libxnet interfaces that includes the following members:
void *msg_name /* optional address */
socklen_t msg_namelen /* size of address */
struct iovec *msg_iov /* scatter/gather array */
int msg_iovlen /* members in msg_iov */
void *msg_control /* ancillary data, see below */
socklen_t msg_controllen /* ancillary data buffer len */
int msg_flags /* flags on received message */
The
<sys/socket.h> header defines the
cmsghdr structure for
libxnet that
includes the following members:
socklen_t cmsg_len /* data byte count, including hdr */
int cmsg_level /* originating protocol */
int cmsg_type /* protocol-specific type */
Ancillary data consists of a sequence of pairs, each consisting of a
cmsghdr structure followed by a data array. The data array contains the
ancillary data message, and the
cmsghdr structure contains descriptive
information that allows an application to correctly parse the data.
The values for
cmsg_level will be legal values for the level argument to
the
getsockopt() and
setsockopt() functions. The
SCM_RIGHTS type is
supported for level
SOL_SOCKET.
Ancillary data is also possible at the socket level. The
<sys/socket.h> header defines the following macros for use as the
cmsg_type values when
cmsg_level is
SOL_SOCKET.
SCM_RIGHTS Indicates that the data array contains the access rights
(set of open file descriptors) to be sent or received.
SCM_UCRED Indicates that the data array contains a
ucred_t to be
received. The
ucred_t is the credential of the sending
process at the time the message was sent. This is a Sun-
specific, Evolving interface. See
ucred_get(3C).
The IPv4 ancillary data formats are listed below by
cmsg_level and
cmsg_type, along with the associated payload for each.
IPPROTO_IP,
IP_RECVDSTADDR --
SOCK_DGRAM only
ipaddr_t, IP address
IPPROTO_IP,
IP_RECVIF uint_t,
ifIndex number
IPPROTO_IP,
IP_RECVOPTS --
SOCK_DGRAM only
variable-length IP options, up to 40 bytes
IPPROTO_IP,
IP_RECVPKTINFO --
SOCK_DGRAM only
in_pktinfo_t IPPROTO_IP,
IP_RECVSLLA --
SOCK_DGRAM only
struct sockaddr_dl, link layer address
IPPROTO_IP,
IP_RECVTTL --
SOCK_DGRAM only
uint8_t, the IP TTL (time to live)
IPPROTO_IP,
IP_RECVTOS uint8_t, the IP TOS (type of service)
SOL_SOCKET,
SO_UCRED ucred_t The IPv6 ancillary data formats are listed below by
cmsg_level and
cmsg_type, along with the associated payload for each.
IPPROTO_IPV6,
IPV6_PKTINFO in_pktinfo_t IPPROTO_IPV6,
IPV6_TCLASS uint_t IPPROTO_IPV6,
IPV6_PATHMTU ip6_mtuinfo IPPROTO_IPV6,
IPV6_HOPLIMIT uint_t IPPROTO_IPV6,
IPV6_HOPOPTS variable-length IPv6 options
IPPROTO_IPV6,
IPV6_DSTOPTS variable-length IPv6 options
IPPROTO_IPV6,
IPV6_RTHDR variable-length IPv6 options
IPPROTO_IPV6,
IPV6_DSTOPTS variable-length IPv6 options
The
<sys/socket.h> header defines the following macros to gain access to
the data arrays in the ancillary data associated with a message header:
CMSG_DATA(cmsg)
If the argument is a pointer to a
cmsghdr structure, this macro
returns an unsigned character pointer to the data array associated
with the
cmsghdr structure.
CMSG_NXTHDR(mhdr,
cmsg)
If the first argument is a pointer to a
msghdr structure and the
second argument is a pointer to a
cmsghdr structure in the ancillary
data, pointed to by the
msg_control field of that
msghdr structure,
this macro returns a pointer to the next
cmsghdr structure, or a null
pointer if this structure is the last
cmsghdr in the ancillary data.
CMSG_FIRSTHDR(mhdr)
If the argument is a pointer to a
msghdr structure, this macro
returns a pointer to the first
cmsghdr structure in the ancillary
data associated with this
msghdr structure, or a null pointer if
there is no ancillary data associated with the
msghdr structure.
CMSG_SPACE(
len)
Given the length of an ancillary data object,
CMSG_SPACE() returns
the space required by the object and its
cmsghdr structure, including
any padding needed to satisfy alignment requirements. This macro can
be used, for example, to allocate space dynamically for the ancillary
data. This macro should not be used to initialize the
cmsg_len member
of a
cmsghdr structure. Use the
CMSG_LEN() macro instead.
CMSG_LEN(
len)
Given the length of an ancillary data object,
CMSG_LEN() returns the
value to store in the cmsg_len member of the
cmsghdr structure,
taking into account any padding needed to satisfy alignment
requirements.
The
<sys/socket.h> header defines the
linger structure that includes the
following members:
int l_onoff /* indicates whether linger option is enabled */
int l_linger /* linger time, in seconds */
The
<sys/socket.h> header defines the following macros:
SOCK_DGRAM Datagram socket
SOCK_STREAM Byte-stream socket
SOCK_SEQPACKET Sequenced-packet socket
The
<sys/socket.h> header defines the following macros for use as the
level argument of
setsockopt() and
getsockopt().
SOL_SOCKET Options to be accessed at the socket level, not the
protocol level.
SOL_ROUTE Options to be accessed at the routing socket level, not the
protocol level.
The
<sys/socket.h> header defines the following macros for use as the
option_name argument of
getsockopt() or
setsockopt() calls:
SO_DEBUG Debugging information is being recorded.
SO_ACCEPTCONN Socket is accepting connections.
SO_BROADCAST Transmission of broadcast messages is supported.
SO_REUSEADDR Reuse of local addresses is supported.
SO_KEEPALIVE Connections are kept alive with periodic messages.
SO_LINGER Socket lingers on close.
SO_OOBINLINE Out-of-band data is transmitted in line.
SO_SNDBUF Send buffer size.
SO_RCVBUF Receive buffer size.
SO_ERROR Socket error status.
SO_TYPE Socket type.
SO_RECVUCRED Request the reception of user credential ancillary data.
This is a Sun-specific, Evolving interface. See
ucred_get(3C).
SO_MAC_EXEMPT Mandatory Access Control (
MAC) exemption for unlabeled
peers. This option is available only if the system is
configured with Trusted Extensions.
SO_ALLZONES Bypass zone boundaries (privileged).
The
<sys/socket.h> header defines the following macros for use as the
valid values for the
msg_flags field in the
msghdr structure, or the
flags parameter in
recvfrom(),
recvmsg(),
sendto(), or
sendmsg() calls:
MSG_CTRUNC Control data truncated.
MSG_EOR Terminates a record (if supported by the protocol).
MSG_OOB Out-of-band data.
MSG_PEEK Leave received data in queue.
MSG_TRUNC Normal data truncated.
MSG_WAITALL Wait for complete message.
MSG_NOSIGNAL Do not generate
SIGPIPE signal.
The
<sys/socket.h> header defines the following macros:
AF_UNIX UNIX domain sockets
AF_INET Internet domain sockets
The
<sys/socket.h> header defines the following macros:
SHUT_RD Disables further receive operations.
SHUT_WR Disables further send operations.
SHUT_RDWR Disables further send and receive operations.
libsocket Interfaces
The
<sys/socket.h> header defines the
msghdr structure for
libsocket interfaces that includes the following members:
void *msg_name /* optional address */
socklen_t msg_namelen /* size of address */
struct iovec *msg_iov /* scatter/gather array */
int msg_iovlen /* # elements in msg_iov */
caddr_t msg_accrights /* access rights sent/received */
The
msg_name and
msg_namelen parameters specify the destination address
when the socket is unconnected The
msg_name can be specified as a
NULL pointer if no names are desired or required. The
msg_iov and
msg_iovlen parameters describe the scatter-gather locations, as described in
read(2). The
msg_accrights parameter specifies the buffer in which access
rights sent along with the message are received. The
msg_accrightslen specifies the length of the buffer.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
SEE ALSO
getpeerucred(3C),
ucred_get(3C),
libsocket(3LIB),
accept(3SOCKET),
bind(3SOCKET),
connect(3SOCKET),
getpeername(3SOCKET),
getsockname(3SOCKET),
getsockopt(3SOCKET),
listen(3SOCKET),
recv(3SOCKET),
recvfrom(3SOCKET),
recvmsg(3SOCKET),
send(3SOCKET),
sendmsg(3SOCKET),
sendto(3SOCKET),
setsockopt(3SOCKET),
shutdown(3SOCKET),
sockaddr(3SOCKET),
socket(3SOCKET),
socketpair(3SOCKET),
accept(3XNET),
bind(3XNET),
connect(3XNET),
getpeername(3XNET),
getsockname(3XNET),
getsockopt(3XNET),
listen(3XNET),
recv(3XNET),
recvfrom(3XNET),
recvmsg(3XNET),
send(3XNET),
sendmsg(3XNET),
sendto(3XNET),
setsockopt(3XNET),
shutdown(3XNET),
socket(3XNET),
socketpair(3XNET),
attributes(7),
standards(7) September 18, 2020
SOCKET.H(3HEAD)